Face-centered Cubic Structure Research Articles

Room Temperature Synthesis of Ordered Intermetallic Electrocatalysts

The conversion of O2 to H2O is an important fuel cell reaction for the recovery of renewable electricity from chemical fuels. Alloys of Pt-group metals (PGMs) with transition metals have emerged as catalysts with enhanced activity and durability for the oxygen reduction reaction (ORR). To date, most studies focus exclusively on alloys that adopt a Face-centered cubic (FCC) or Face-centered tetragonal (FCT) crystal lattice. Under ORR operating conditions, these materials evolve from alloys to Pt core-alloy shell materials, in this case both the alloy core and Pt shell retains the FCC or FCT type crystal structure; indicating that materials can dynamically change during catalysis.Here we present the synthesis of Pd-Bi based ordered intermetallics by partial dealloying of a Bi rich alloy. We found that under ORR operation conditions, β-PdBi2 (I4/mmm space group) which adopts a tetragonal lattice, transforms to α-Pd3Bi (Pmma space group) which adopts an orthorhombic crystal structure; this transformation is mediated by oxidative Bi corrosion under potential cycling, and reconstruction of the atoms in the bulk. To the best of our knowledge, this is the first report of a material that exhibits an electrochemically driven, non-congruent phase transition among materials with different crystal structures. The resulting phase-converted Pd3Bi is stable and exhibits high performance for ORR. Phase-converted Pd3Bi outperform Pt and Pd metal, reaching mass activities of 2.6 A/mgPd, which is nearly 10X higher than Pt/C (~0.3 A/mgPt) and Pd/C (~0.2 A/mg) at 0.9 V vs the Real Hydrogen Electrode (RHE). The mass activity of Pd3Bi decreases by ~38% after 10,000 cycles, indicating that it is stable. Activation energy (Ea) determined by temperature dependent electro-kinetic measurements indicates that the activity enhancement on phase-converted Pd3Bi originates from anion-poisoning resistant behavior. These results establish that PGMs-based ordered intermetallics with low-symmetry crystal structures can be highly active and durable electrocatalysts.

Effect of vibration mode on self-assembly of granular spheres under three-dimensional vibration

This paper presents a numerical study on the self-assembly of mono-size granular spheres with periodic boundary conditions under uniform and non-uniform 3D vibration. For uniform 3D vibration, the vibration conditions for self-assembly are similar to those under 1D vertical vibration. For non-uniform 3D vibration, slight horizontal vibration added to 1D vertical vibration can significantly promote or depress self-assembly. Moreover, under 1D or uniform 3D vibration, self-assembly results in a RHCP (random hexagonal close packed) structure, while under certain non-uniform vibration, a packing can self-assemble into a nearly pure FCC (face centered cubic) or HCP (hexagonal close packed) crystal structure. The microscopical analyses on the local structures, dynamics and forces provide rich insight into the different self-assembly processes under different vibration modes. These results can help understand the self-assembly of granular materials under vibration and guide how to control the structure of packed beds.

Microstructure and Mechanical Properties of Face‐Centered‐Cubic‐Based Cr‐Free Equiatomic High‐Entropy Alloys

High‐entropy alloys (HEAs) with face‐centered‐cubic (FCC) structures, e.g., the typical CrMnFeCoNi HEA, have a strong tendency to precipitate brittle sigma phases, as Cr is a strong sigma stabilizer. To develop HEAs with alleviated concerns of sigma phases, Cu for Cr in the Cr‐Mn‐Fe‐Co‐Ni HEA system is substituted to form a Mn‐Fe‐Co‐Ni‐Cu system. The quinary alloy and its quaternary subsets are investigated all in as‐cast state. Microstructure evolution, phase constituent, and tensile properties at room temperature are studied. The HEAs have multi‐phase FCC structures with slightly different lattice constants and spherical Cu‐rich particles are observed in most systems. All alloys exhibit dendrite‐like morphology with Cu segregation in interdendritic regions due to the solute partitioning. The investigated HEAs show good strengths, large elongations, and work hardening capability. The strengths are attributed to combined mechanisms, especially the precipitation strengthening by Cu‐rich particles. The findings provide some model HEA systems for further usefully guiding design in the widely compositional space of Cr‐free HEAs.

Deformation mechanism of pure hafnium under high speed compression

The microstructures and mechanical properties of Hf compressed at the strain rates of 300 s−1、1290 s−1 and 2800 s−1 were investigated. At a strain rate of 300 s−1, dislocation slip dominated the deformation. Meanwhile, a small number of the face-centered cubic (FCC) lamellas formed via hexagonal close-packed (HCP) structure to FCC structure transformation. As the strain rate increased to 1290 s−1, both the dislocation density and the number of the FCC lamellas increased significantly. When the strain rate reached 2800 s−1, dislocation slip, phase transformation, twinning, dynamic recrystallization and shear banding occurred in the material. However, the number of the FCC lamellas decreased significantly at the strain rate of 2800 s−1, indicating that the HCP to FCC phase transformation was restrained. The temperature rise inside the specimens compressed under the strain rate of 2800 s−1 promoted deformation twinning and dynamic recrystallization. The microhardness increased gently for the specimens compressed at strain rates of 300 s−1 and 1290 s−1, while when the strain rate increased to 2800 s−1, the microhardness increased substantially. The formation of various boundary structures, including microbands, twins and FCC bands, contributes to the hardness increase by acting as obstacles to dislocation motion. In addition, the formation of new grains by dynamic recrystallization also played a role in strengthening.

First-principles study of phase stability, elastic and thermodynamic properties of AlCrFeNi medium-entropy alloys

We have applied the first-principles method to predict the phase stability, elastic and thermodynamic properties of ternary (AlCrFe, AlCrNi, CrFeNi and AlFeNi) and quaternary (AlCrFeNi) medium-entropy alloys (MEAs). Both body-centered cubic (BCC) and face-centered cubic (FCC) disordered structures are described using the special quasi-random structures (SQSs) technique. AlCrFe, AlCrNi and AlCrFeNi are favorable in single BCC structures, while CrFeNi is likely to form a single FCC structure. Addition of Ni help stabilizes AlCrFeNi quaternary MEAs. Al and Cr addition are in favor of the formation of BCC AlCrFeNi. Addition of Al, Cr and Ni reduce the resistance to volume deformation for quaternary AlCrFeNi due to the effect of the average number of [Formula: see text]-electrons. The ternary MEAs have better resistance to shear deformation and elastic stiffness than quaternary AlCrFeNi. In addition, all the considered MEAs embody elastic anisotropy and AlCrFeNi are predicted to be ductile behavior. Finally, volumetric thermal expansion coefficient, constant volume heat capacity, vibrational and electronic entropy, and Helmholtz free energies of stable BCC AlCrFeNi, BCC AlCrFe, BCC AlCrNi and FCC CrFeNi are calculated using the Debye–Grüneisen model in temperature ranging from 0 to 1200 K to elucidate the relationships between thermodynamic parameters and temperature.

Tribological behavior of boronized Al0.1CoCrFeNi high-entropy alloys under dry and lubricated conditions

High-entropy alloys (HEAs) with a single-phase face-centered cubic (FCC) structure generally have excellent plasticity. However, its limited room temperature strength and hardness result in lower wear resistance, which hinders tribological and engineering applications. In this paper, the pack-boronizing method was used to improve the tribological properties of Al0·1CoCrFeNi HEAs with a single-phase FCC structure. The boronizing treatment was carried out at 900 °C for 2, 4, 6, and 8 h, respectively. The structure and phase formation of boronized alloys were studied. Moreover, the reciprocating sliding wear behavior of boronized alloys against Si3N4 balls in dry and deionized water was investigated. A boronized layer with a double-layer structure was formed on the HEA surface, with a total thickness of about 17.3–58.5 μm. The wear mechanism of boronized alloy was transformed from the abrasive and delamination wear to the polishing effect with increasing the boronizing time in air. In contrast, the wear mechanism of boronized alloys in the deionized water gradually changed from the two-body to three-body wear with increasing the boronizing time. Meanwhile, the wear mechanism of the Si3N4 counterface was also transformed to three-body wear gradually.

Hierarchical self-assembly of supramolecular polymer complexes mediated by various generations of bent-core mesogenic dendrimers hydrogen-bonded with triblock copolymer

A series of side-chain supramolecular polymer complexes containing proton acceptor triblock copolymer, i.e., poly(4-vinylpyridine)-block-polystyrene-block-poly(4-vinylpyridine) (VSV, i.e., P4VP-PS-P4VP), hydrogen-bonded (H-bonded) with two generations of proton donor bent-core mesogenic dendritic pendants (G1 and G2) were prepared and investigated. These two supramolecular polymer complexes (i.e., VSV/G1 and VSV/G2) were characterized by wide- and small-angle X-ray scattering (WAXS and SAXS), and the formation of a microphase separated smectic A (SmA) structure corresponding to a head-to-head layered arrangement was confirmed. The hierarchical structures within the morphologies of supramolecular polymer complexes were proved not only by the SAXS patterns but also by the transmission electron microscopy (TEM). The novel hierarchical lamellar domains of corresponding tetragonal and hexagonal arrangements in different generations of dendritic proton donors (G1 and G2) were self-assembled with triblock copolymer proton acceptor VSV to induce respective BCC (body-centered cubic) and FCC (face-centered cubic) structures in supramolecular polymer complexes VSV/G1 and VSV/G2. Therefore, the shear alignments of characteristic cylindrical column phase micro-domains were developed for the first time to control the unique hierarchical constructions of functionalized self-assembled bent-core structures by utilization of various generations of dendritic proton donors to be H-bonded with triblock copolymer proton acceptor.

Mechanical design and energy absorption performances of novel dual scale hybrid plate-lattice mechanical metamaterials

In this paper, novel dual scale hybrid mechanical metamaterials consisting of simple cubic structure (SC), body-centered cubic structure (BCC), face-centered cubic structure (FCC) unit cells at different scale levels were designed and proposed for impact energy absorption, where one large type A unit cell and eight (2 × 2 × 2) small periodicspatially architected type B unit cells with half size of type A unit cell along X, Y and Z directions were integrated together for harvesting final hybrid metamaterials. Comparisons of specific energy absorption performances between novel hybrid mechanical metamaterials and constituent simple single type of unit cell lattice during compression process were performed through experimental investigation, where the failure and energy absorption process were recorded using the digital camera. Afterwards, finite element analysis (FEA) was performed and compared with experimental results for investigating the mechanical benefits of novel hybrid Plate-lattice mechanical metamaterials, it was found that the novel hybrid plate-lattice mechanical metamaterials can generate enhanced specific strength, specific stiffness and elevated energy absorption performances indicators, demonstrated promising industrial application potentials as energy-absorbing materials and structures for aerospace, vehicles, transport industrial sections.

Viscoplastic effects on plane strain fracture of FCC and BCC single crystals

In the present work, simulations of mode I crack growth and plastic yielding at a crack tip in a plane strain crystal are considered. The theory of crystal plasticity is used and the analyses are made for small strains and rotations. The crack tip is considered as if it is inserted in a metallic grain (single crystal). Two types of crystals are simulated: face-centered cubic (FCC) and body-centered cubic (BCC). The crack growth zone is modeled by cohesive interfaces whose separation process is described by a cohesive zone model. The material and the cohesive surfaces have independent constitutive relations and fracture is an outcome of the deformation process. The cohesive tractions are implemented within the finite element method model through the principle of virtual work. A finite element mesh with rectangular bilinear elements is combined with cohesive elements to model the structure. BCC structures showed a greater toughness than FCC structures in the orientation tested, considering all other properties the same. Viscous properties influence on fracture—crack growth characteristics such as crack extension and time for the beginning of the growth process—were also explored and direct comparisons between the two types of crystal were made. In these cases, FCC crystals showed a greater rate dependency than BCC.

Dynamic Behavior of the Structural Phase Transition of Hydrogel Formation Induced by Temperature Ramp and Addition of Ibuprofen.

Understanding the dynamic behavior of hydrogel formation induced by a temperature ramp is essential for the design of gel-based injectable formulation as drug-delivery vehicles. In this study, the dynamic behavior of the hydrogel formation of Pluronic F108 aqueous solutions within different heating rates was explored in both macroscopic and microscopic views. It was discovered that when the heating rate is increased, the gelation temperature window (hard gel region) shrinks and the mechanical strength of the hydrogel decreases. A given system at different heating rates would lead to different crystalline structural evolutions. The time-resolved small-angle X-ray scattering (SAXS) experiments at a heating rate of 10 °C/min disclose that the crystalline structure of micelle packing in the hydrogel exhibits a series of transitions: hexagonal close-packed (HCP) to face-centered cubic (FCC) and body-centered cubic (BCC) structures coexisting and then to the BCC structure along with the increasing temperature. For the system at equilibrium, the BCC structure exclusively dominates the system. Furthermore, the addition of a hydrophobic model drug (ibuprofen) to the F108 aqueous solution promotes hard gel formation at even lower temperatures and concentrations of F108. The SAXS results for the system with ibuprofen at a heating rate of 10 °C/min demonstrate a mixture of FCC and BCC structures coexisting over the whole gelation window compared to the BCC structure that exclusively dominates the system at equilibrium. The addition of ibuprofen would alter the structural evolution to change the delivery path of the encapsulated drug, which is significantly related to the performance of drug release.

Pleurotus sajor-caju-Mediated Synthesis of Silver and Gold Nanoparticles Active against Colon Cancer Cell Lines: A New Era of Herbonanoceutics.

Herbal medicines are widely used worldwide and much appreciated because of their fewer side effects and the ability to fight diseases at the root cause. Active ‘phyto’ ingredients require a scientific approach and a mechanism to distribute components at the target site for better therapeutic results. Nanotechnology, on the other hand, has created new hope for cancer treatment but is still far from being proven in clinical settings. This article combines a unique approach to synthesis with the use of Pleurotus sajor-caju, followed by microwave irritation of silver and gold nanoparticles that ensures the capping of the active phyto ingredient and further enhances the effects of nanomedicine to fight colon cancer, thus opening a new era of what we call herbonanoceutics. The article also compares the characteristics and properties of silver (Au) and gold (Ag) nanoparticles synthesized by an in house developed novel microwave-assisted rapid green synthesis method. The as-prepared Ag NPs and Au NPs were compared using ultraviolet-visible spectroscopy (UV-Vis), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), and energy dispersive spectroscopy (EDS). Our comparative study revealed that both assemblies display face-centred cubic structures (FCCs) and are nanocrystalline in nature. The advantage of the approach was that the sizes of gold and silver were identical in range with a similar distribution pattern. This has helped us to study the activity against colon cancer cell line (HCT-116) without incoherence since size plays a key role in the application. More specifically, morphological changes, cell viability, the production of reactive oxygen species (ROS) and the fragmentation of DNA have been further reported to assess better the results obtained with the two metals. Our results suggest that the newly adopted synthesis method may ensure the dual benefits from phyto ingredients which further enhances the effectiveness of advanced nanomedicine.

Structure-property relationships in hot forged AlxCoCrFeNi high entropy alloys

AlxCoCrFeNi is one of the most extensively studied high entropy alloy systems, as it has shown excellent mechanical properties suitable for structural applications. In this work, AlxCoCrFeNi(x = 0.3, 0.5, 0.7) alloys were successfully hot-forged without any visible cracks. Contributions from different strengthening mechanisms were estimated and compared with the experiment. Optical microscopy, x-ray diffraction (XRD), electron backscatter diffraction (EBSD), energy dispersive x-ray spectroscopy (EDS) and hardness tests were used for structural and mechanical property analysis. A single-phase face centered cubic (FCC) structured was observed in the as-cast Al0.3 alloy, whereas, dual-phase FCC and body centered cubic (BCC) structures were observed in the as-cast Al0.5 and Al0.7 alloys. An increase in the FCC phase fraction was observed in all the alloy compositions after forging. Microstructure analysis revealed that phase fraction, the formation of twins, low angle grain boundaries, and grain refinement played a vital role in strengthening the alloy systems. After forging, the hardness of the Al0.3 and Al0.5 alloys was increased by 22% and 48%, respectively. In contrast, a reduction of 8% in hardness was observed in Al0.7 alloy. Reduction in the hardness is mainly due to higher FCC phase fraction and interface stress in forged Al0.7 alloy. A new modified rule of mixture is proposed to estimate the total strength of dual-phase high entropy alloys.

Synthetic Effect of Cr and Mo Elements on Microstructure and Properties of Laser Cladding NiCrxMoy Alloy Coatings

NiCrxMoy (x = 1, 1.5; y = 0, 0.1, 0.3) alloy coatings were prepared on the Q235 substrate by laser cladding under the protection of argon. The phase composition, microstructure, corrosion behavior, and mechanical properties of the NiCrxMoy alloy coatings were investigated using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, electrochemical tests, X-ray photoelectron spectroscopy, microhardness, and nanoindentation tests. As the Cr content increased, the phase composition of the coatings changed from a single face-centered cubic (FCC) structure to a dual-phase structure coexisting with body-centered cubic (BCC) and FCC structures, while the addition of Mo promoted the precipitation of σ phase. The appearance of a homogeneous dual-phase structure and some amount of σ phase played a positive role in the corrosion resistance of NiCrxMoy coatings. Cr3+ ions and Mo6+ ions in the passive film enhanced the stability of the coatings. The nanoindentation tests showed that the nanohardness (6.71 GPa) and elastic modulus (184.40 GPa) of BCC phase were higher than those of the FCC phase (5.19 GPa and 155.26 GPa, respectively). Overall, the BCC phase and σ phase improved the mechanical properties of the coatings.

Micrometric Monodisperse Solid Foams as Complete Photonic Bandgap Materials.

Solid foams with micrometric pores are used in different fields (filtering, 3D cell culture, etc.), but today, controlling their foam geometry at the pore level, their internal structure, and the monodispersity, along with their mechanical properties, is still a challenge. Existing attempts to create such foams suffer either from slow speed or size limitations (above 80 μm). In this work, by using a temperature-regulated microfluidic process, 3D solid foams with highly monodisperse open pores (PDI lower than 5%), with sizes ranging from 5 to 400 μm and stiffnesses spanning 2 orders of magnitude, are created for the first time. These features open the way for exciting applications, in cell culture, filtering, optics, etc. Here, the focus is set on photonics. Numerically, these foams are shown to open a 3D complete photonic bandgap, with a critical index of 2.80, thus compatible with the use of rutile TiO2. In the field of photonics, such structures represent the first physically realizable self-assembled FCC (face-centered cubic) structure that possesses this functionality.

Molecular dynamics simulation of size, temperature, heating and cooling rates on structural formation of Ag-Cu-Ni ternary nanoparticles (Ag34-Cu33-Ni33)

We used molecular dynamics (MD) simulations with embedded atom method (EAM) potential to investigate the effect of size, simulation temperature heating and cooling rates on the nanoparticle formations, elemental distributions, melting, crystallization and phase transitions in equiatomic Ag-Cu-Ni ternary nanoparticle systems. Five model systems consisting of N = 412, 1348, 3173, 6222 and 10,843 total atoms of pure, metallic, single-oriented, spherical silver (Ag), copper (Cu) and nickel (Ni) particles used. A two-step heating process including relaxing and heating with fast, 1 × 1013 K s−1 and slow, 1 × 1011 K s−1 heating rates applied to monometallic Ag, Cu, Ni and ternary AgCuNi clusters to study melting behavior of systems. We obtained melting temperatures for various systems and found structural and morphological changes depend on the number of atoms in ternary cluster. A four-step thermal process including relaxing, heating, annealing and cooling applied to model systems to study effects of temperature (T = 1000, 1500 and 2000 K) and cooling rates (fast, 1 × 1013 K s−1 and slow, 1 × 1011 K s−1) for crystallization. We detected core–shell structure, Ag@CuNi for all simulations because of surface energy. The total energy of ternary clusters decrease linearly with increasing N, revealing similar mechanisms govern for core–shell structure and phase transitions. Energy-Temperature data of slow cooling rate have shown phase transition (crystallization) for monometallic Ag, Cu, Ni and ternary AgCuNi clusters, increasing with N. Fast cooling rate influences energy configuration and result in amorphous phases. Polyhedral template matching method applied to study phase transitions. For slow cooled clusters, face-centered cubic (FCC) and hexagonal close packed (HCP) structures are dominant while for fast cooled clusters, we observed amorphous phases with HCP and icosahedral structures. Furthermore, we used centrosymmetry parameter to identify the origin of the FCC structure. Our data show increasing simulation temperature and decreasing cooling rate favor crystallization of ternary AgCuNi clusters.

The tension-compression asymmetry of martensite phase transformation in a metastable Fe40Co20Cr20Mn10Ni10 high-entropy alloy

The microstructural evolution of a metastable face centered cubic (FCC) Fe40Co20Cr20Mn10Ni10 high-entropy alloy (HEA) under both tension and compression is systemically investigated. The results show much higher level of martensite phase transformation from FCC structure to hexagonal closed packed (HCP) structure under compression than tension, indicating a distinct tension-compression asymmetry. The compressive tests underwent higher true stresses, which further provided stronger driving forces to trigger the phase transformation than those in tensile tests. Except for the martensite phase transformation, dislocation planar slip prevails in both tension and compression, along with the occasional formation of mechanical twins. Dislocation slip dominates the whole tensile deformation, while both dislocation motions and martensite phase transformation play critical roles in the compressive deformation. The martensite phase transformation is preferred to nucleate at grain or subgrain boundaries due to a medium stacking fault energy (SFE) of ∼20 mJ m−2. The formation of HCP phase via partial dislocation emission from low angle grain boundaries offers additional pathways for martensite phase transformation. Our study thus remarkably benefits the understanding of the de formation mechanisms of metastable HEAs.

Methanol steam reforming microreactor with novel 3D-Printed porous stainless steel support as catalyst support

In order to study the methanol steam reforming performance of the 3D-printed porous support for hydrogen production, three dimensional (3D) printing technology was proposed to fabricate porous stainless steel supports with body-centered cubic structure (BCCS) and face-centered cubic structure (FCCS). Catalyst loading strength of the 3D-printed porous stainless steel supports was studied. Moreover, methanol steam reforming performance of different 3D-printed porous supports for hydrogen production was experimentally investigated by changing reaction parameters. The results show that the 3D-printed porous stainless steel supports with BCCS and FCCS exhibit better catalyst loading strength, and can be used in the microreactor for methanol steam reforming for hydrogen production. Compared with 90 pores per inch (PPI) Fe-based foam support, 3D-printed porous stainless steel supports with FCCS and BCCS show the similar methanol steam reforming performance for hydrogen production in the condition of 6500 mL/(g·h) gas hourly space velocity (GHSV) with 360 °C reaction temperature. This work provides a new idea for the structural design and fabrication of the porous support for methanol steam reforming microreactor for hydrogen production.

Capturing the Equilibration Pathway of Nanomaterials Metastable in Both Crystal Structure and Morphology

In this issue of Matter, Li et al. used in situ electron microscopy to investigate the equilibration pathway of Au nanoribbons that are metastable in terms of both crystal structure and morphology when they are subjected to thermal stress.

Phase transformation and structural evolution in a Ti-5at.% Al alloy induced by cold-rolling

The phase transformation, deformation mechanism and their correlation in a cold-rolled Ti-5at.%Al alloy were investigated. Two types of phase transformations from a hexagonal close-packed (HCP) structure to a face-centered cubic (FCC) structure were observed: the basal-type (B-type) with an orientation relationship of <12-10>HCP//<11-0>FCC and {0001}HCP//{111}FCC, and the prismatic-type (P-type) with an orientation relationship of <12-10>HCP//<11-0>FCC and {101-0}HCP//{110}FCC. The two types of transformations both accommodate the strain along the < c> axis of the HCP matrix. With the proceeding of deformation, different deformation mechanisms were activated in the FCC and the HCP structures, respectively, which led to a faster grain refinement rate in the FCC structure than in the HCP matrix. Deformation twins with zero macroscopic strain were prevalent in the FCC domains produced by the B-type transformation, while deformation twins with macroscopic strain were normally observed in the FCC domains produced by the P-type transformation. This is in accordance with the lattice mismatches produced during phase transformation. The easy occurrence of deformation twinning in the FCC structure contributed significantly to the grain refinement process. In addition, the interaction between neighboring FCC domains produced by the two types of phase transformations also accelerated the grain refinement process.

Influence of Cr content on the microstructure and mechanical properties of CrxFeNiCu high entropy alloys

The effect of Cr content on the microstructure and mechanical properties of CrxFeNiCu high entropy alloys (HEAs) was firstly studied by first-principles calculations. The calculated results show that the hardness of the alloys increased with the expense of its plasticity decrease, if the content of Cr in the alloy increased. In order to verify the calculated results, CrxFeNiCu (x = 0.8, 1, 1.5 and 2) high entropy alloys were synthesized by vacuum induction melting in the present study. The results show that as the value of x increased from 0.8 to 2, the crystal structure changed from single phase face centered cubic (FCC) phase to a mixture of FCC and body centered cubic (BCC) phases. For the single phase FCC (x = 0.8) structure, both the tensile strength and hardness values were low, which were 491.6 MPa and 322.2 HV respectively, however, the plasticity was high, reaching 33.2%. With the formation and growth of BCC phase (x = 2) the tensile strength and hardness of the alloy were significantly improved, which were 872.6 MPa and 808 HV, respectively.